You've got thirteen spooktastic skeins inspired by the Scary Stories to Tell in the Dark trilogy -- now what?? Below are a few patterns that would look just stunning. 

Note: not all of these are written for multiple colors, but with a few creative adjustments they could easily be adapted to marl, fade, or stripe the set.

Links below lead to Ravelry

DK:

Perfectionist Trap (knit)  (This pattern can also work with any weight yarn)

Agate Cowl (crochet) by KnotBadBritt 

Memento Mori (crochet) by Melody Martinez

Ghost Town (knit) by Carlie Perrins

Boneyard (knit) by Stephen West 

Ginger Cowl (crochet) by Toni Lipsey

Fingering:

I Am Dragon (knit) by Alexandra Davidoff 

Crochet Your Fade (crochet) by Julme Conradie

Solstice Wrap (knit) by Ambah O'Brien

Top Down Skulls  (crochet) by Fille Wegler

Lift Your Spirits (crochet) by Amanda Mannas

The Insomniac (knit) by Casapinka

Gone Camping (knit) by Josh Bennett

Strychnine (knit) by MMario 

Worsted

Fading Guernsey (knit) by Robbie Laughlin

Hipster (knit) by Joji Locatelli

A Practical Witch Hat (knit) by tiny owl knits

Scrappy Granny Shawl (crochet) by Regina Weiss

Skulls Scarf (crochet) by Holly Bailey

More ideas!

Not your style? If Ravelry is accessible to you, try searching "advent" and see if anything catches your eye!

Try using the full skein as the MC in a colorwork project, with the mini skeins in gradient order as the CC!

Another suggestion: marl or fade the skeins together in a pattern that calls for similar yardage and one color. This is my favorite way to make a pattern unique and my own - and it keeps the stitching so interesting!

For some information on working with fades/graidents, Oliphant Kat has written a great primer.

If you'd like to dip into marling, Tin Can Knits has (as usual!) created a very helpful guide.